根据下面材料，回答题。HumanHeartCanMakeNewCellSolvingalongstandingmystery,scientistsha

共享题干题根据下面材料，回答题。 Human Heart Can Make New Cell Solving a longstanding mystery, scientists have found that the human heart continues to generate new cardiac cells throughout the life span, although the rate of new cell production slows with age. The finding, published in the April 3 issue of Science, could open a new path for the treatment of heart diseases such as heart failure and heart attack, experts say. "We find that the beating cells in the heart, cardiomyocytes, are renewed," said lead researcher Dr. Jonas Frisen, a professor of stem cell research at the Karolinska Institute in Stockholm, Sweden. "It has previously not been known whether we were limited to the cardiomyocytes we are born with or if they could be renewed," he said. The process of renewing these ceils changes over time, Frisen added. In a 20-year-old, about 1 percent of cardiomyocytes are exchanged each year, but the turnover rate decreases with age to only 0.45 percent by age 75. "If we can understand how the generation of new cardiomyocytes is regulated, it may be potentially possible to develop pharmaceuticals that promote this process to stimulate regeneration after, for example, a heart attack," Frisen said.That could lead to treatment that helps restore damaged hearts. "A lot of people suffer from chronic heart failure," noted co-author Dr.Ratan Bhardwaj, also from the Karolinska Institute. "Chronic heart failure arises from heart cells dying," he said.With this finding, scientists are "opening the door to potential therapies to having ourselves heal ourselves," Bhardwaj said. "Maybe one could devise a pharmaceutical agent that would make heart cells make new and more cells to overcome the problem they are facing." But barriers remain. According to Bhardwaj, scientists do not yet know how to increase heart cell production to a rate that would replace cells faster than they are dying off, especially in older patients with heart failure. In addition, the number of new cells the heart produces was estimated using healthy hearts--whether the rate of cell turnover in diseased hearts is the same remains unknown.1.[不定向选择题]The human heart stops producing cardiac cells____________.A.when a person is born B.when a person becomes old C.when a person gets sick D.when a person die 2.[不定向选择题]The finding could prove to be helpful to____________.A.the study of longstanding mysterie B.the analysis of cardiac cell C.the prevention of chronic disease D.the treatment of heart disease

1.参考答案：D
参考解析：细节题。题干：__________，人类的心脏停止产生心脏细胞。利用题干关键词可以定位到短文的第一段，即科学家们发现，在人的整个生命过程中，其心脏不断产生新的心肌细胞。言外之意，这个过程直到人死了才会停止。?
2.参考答案：D
参考解析：细节题。题干：这一发现被证明对__________有益。利用题干关键词可以定位到短文的第二段，即这一发现将为心脏病的治疗开辟新的途径。?3.[不定向选择题]Chronic heart failure is associated with____________.A.the death of heart cell B.the life span of a person C.the effects of pharmaceutical D.the weight of the patient

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